Section 5. Such boards may lay out and improve public parks, make rules for their use and government, appoint all necessary engineers, surveyors, clerks and other officers, including a police force to act in such parks, define their powers and duties and fix their compensation and do all acts needful for the proper execution of their powers and duties. They shall have the authority given to the mayor, aldermen, selectmen, road commissioners and tree warden respectively by section seven of chapter eighty-four and by chapter eighty-seven, in places under their jurisdiction. Subject to appropriation, such boards shall also have the power to conduct park programs and recreation activities at places other than such public parks.